1. Field of the Invention
The invention relates to an actuating device with a rotatable cup-shaped locking head for multi-point safety belts.
2. Description of the Related Art
In accordance with a known type of construction which has been incorporated into the applicable safety standards, actuating devices for multi-point safety belts, particularly for racing cars, are constructed as levers. The levers protrude above the flat plane of the base member as well as beyond the diameter thereof; this is in order to achieve a good accessibility as well as in order to reduce the force to be applied, so that a lock can still be actuated even after an accident.
In aircraft construction, actuating devices are either equipped with substantially grooved locking heads or with very smooth cup-shaped locking heads.
The first embodiment is intended to achieve a sufficient frictional engagement between the hand of the user and the actuating device. However, the first embodiment has the disadvantage that, for example, pilots during the check prior to departure will unintentionally engage the check list holder in one of the grooves and will unintentionally open the lock because the angular movement of about 30.degree. to 40.degree. is kept relatively small in these locks.
In order to prevent these disadvantages, smooth cup-shaped constructions were used in the second embodiment. However, these constructions have the disadvantage that, when loosening the belt, i.e., when actuating the lock, a user must grasp the lock with a hand which is curved like a trough in order to produce a sufficient fictional engagement for actuation. However, it is known that a hand which has sustained an injury especially on the back of the hand is no longer able to carry out such a grasping function. Moreover, in a safety belt which is used in an ambulance aircraft, the use of such an actuating device leads to substantial safety risks because its actuation with the hand of a rescue worker which may be covered, for example, with medicaments or even blood, is hardly possible any more because of the particularly low coefficient of friction.